Analysis of the Failure Tolerance of Linear Access Networks

In this paper, we study the disconnection of a moving vehicle from a linear access network composed by cheap WiFi Access Points in the context of the telecommuting in massive transportation systems. In concrete, we analyze the probability for a user to experience a disconnection longer than a threshold t*, leading to a disruption of all on-going communications between the vehicle and the infrastructure network. We provide an approximation formula considering two scenarios (intercity bus and train) to estimate this probability for large networks. We then carry out a sensitivity analysis and supply a guide for operators when choosing the parameters of the networks. Last, we show that such systems are viable, as they attain a very low probability of long disconnections with a very low maintenance cost.